1. Field of the Invention
This invention relates to building construction and more specifically to building construction methods that employ prefabrication complementing on-site construction.
2. Prior Art
Prefabricated building construction is well known, including prefabricated homes that are fully constructed in a factory and then shipped to a desired location for installation. Multiple units can be combined on site to result in a building larger than a single unit, which is limited in size to that which can be transported on a truck. Concrete structures are also known. One method is to pour concrete into slab panels at a manufacturing site, transport the panels to the building site and crane the panels together to form the desired shape of the structure. In most cases this method has proved not to be cost effective. Therefore, due to the weight and fragility of concrete panels, most concrete structures are cast on site, which typically means that forms are built and set into a framework and the concrete is poured into the formwork at the building site. The structure is then lifted by a crane into place.
Concrete castings, onsite and offsite, may include some utilities but generally they comprise only basic conduits and pipes needed for the project. Additional utilities are still needed. Installing these additional utilities requires the trades and inspectors to visit the site several times, which adds cost to the construction project.
Previous concrete construction methods typically pour the concrete walls first before other trades perform their work. As a result the framers, plasters, electricians, plumbers, heating contractors and other trades are required to work around and with the already poured structures which in most cases are not perfect. This usually results in mistakes being made, more labor, inspections and in the end more money.
A facility built with concrete walls installed first and following trades later also cannot be previewed. One can only look at plans or examples of previous projects.
The object of the present invention is therefore to provide a method of building construction that is amenable to construction of substantially all of a building inside of external walls (hereinafter “prefabrication unit”) prior to construction or installation of the external walls. It is a further object that the method include prefabrication of a prefabrication unit at a site remote from the building site (the site where the building will be permanently located) and transporting the prefabrication unit to the building site. It is still another object that construction of the prefabrication unit provides access to tradesmen for construction of the prefabrication unit at a site remote from the building site such that the tradesman may complete their work during a single visit to the prefabrication site of the prefabrication unit. It is another object that any prefabricated portion of the building be lightweight to facilitate ease of transport to the building site. It is yet another object that the construction of the building be amenable to installation of concrete walls at the building site after the prefabrication unit is completed or substantially completed. It is a yet further object the concrete walls be poured in place (as opposed to poured on a form on the ground and lifted into place) without causing damage to the prefabrication unit. It is a further object that the prefabrication unit be able to be previewed by customers of their purchased unit prior to installation at their building site and by potential customers at a location remote from the building site, such as dealership ‘showrooms,’ for marketing purposes.